title: Event related potential (ERP) evidence for selective impairment of verbal recollection in abstinent recreational methylenedioxymethamphetamine ("Ecstasy")/polydrug users.
abstract: OBJECTIVE
  Ecstasy is a recreational drug whose active ingredient, 3,4-methylenedioxymethamphetamine (MDMA), acts predominantly on the serotonergic system. Although MDMA is known to be neurotoxic in animals, the long-term effects of recreational Ecstasy use in humans remain controversial but one commonly reported consequence is mild cognitive impairment particularly affecting verbal episodic memory. Although event-related potentials (ERPs) have made significant contributions to our understanding of human memory processes, until now they have not been applied to study the long-term effects of Ecstasy. The aim of this study was to examine the effects of past Ecstasy use on recognition memory for both verbal and non-verbal stimuli using ERPs.
  
  
  METHODS
  We compared the ERPs of 15 Ecstasy/polydrug users with those of 14 cannabis users and 13 non-illicit drug users as controls.
  
  
  RESULTS
  Despite equivalent memory performance, Ecstasy/polydrug users showed an attenuated late positivity over left parietal scalp sites, a component associated with the specific memory process of recollection.
  
  
  CONCLUSIONS
  [corrected] This effect was only found in the word recognition task which is consistent with evidence that left hemisphere cognitive functions are disproportionately affected by Ecstasy, probably because the serotonergic system is laterally asymmetrical. Experimentally, decreasing central serotonergic activity through acute tryptophan depletion also selectively impairs recollection, and this too suggests the importance of the serotonergic system. Overall, our results suggest that Ecstasy users, who also use a wide range of other drugs, show a durable abnormality in a specific ERP component thought to be associated with recollection.
authors.affiliation: School of Life & Health Sciences, Aston University, Aston Triangle, Birmingham, UK. a.p.burgess@aston.ac.uk
authors.forename: Adrian P
authors.initials: AP
authors.lastname: Burgess
authors.forename: Louise
authors.initials: L
authors.lastname: Venables
authors.forename: Helena
authors.initials: H
authors.lastname: Jones
authors.forename: Rhiannon
authors.initials: R
authors.lastname: Edwards
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Parrott
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D003071:Cognition / Q000187:drug effects; D005071:Evoked Potentials / Q000187:drug effects*; D005260:Female; D006213:Hallucinogens / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008568:Memory / Q000187:drug effects*; D018817:N-Methyl-3,4-methylenedioxyamphetamine / Q000009:adverse effects*; D021641:Recognition, Psychology / Q000187:drug effects; D012701:Serotonin / Q000378:metabolism; D013997:Time Factors; D055815:Young Adult
chemical_list: D006213:Hallucinogens; D012701:Serotonin; D018817:N-Methyl-3,4-methylenedioxyamphetamine